A ' 


DEPOSITORY 


Issnrd  May  20, 


U.  S.  DEP  \RTMENT  OF  AGRICULTURE, 

BUREA1     OF  PLANT  [NDUSTRY   -Circular  No.  26. 

B.  T.  GA1  l.<>\\  \V  i 


SOME  FACTORS  AFFECTING  THE  KEEPING 
QUALITIES  OF  AMERICAN  LEMONS. 


RODNEY  II.  TRUE, 
Physiologist  i\  Ch  w.< h  . 

\N!) 

ARTHUR   V.  SIEVERS, 
Expert,  Drug-Plant  Investigations. 


h  .  office  : 


[Cir.  26] 

2 


BUREAU  OF  PLANT  INDUSTRY. 


Chief  of  Bureau,  Beverly  T.  Galloway. 
Assistant  Chief  of  Hunan.  Albert  V.  Woods. 
Editor,  J.  E.  Rockwell. 
Chief  Clerk,  James  E.  Jones. 


B.  P.  I.-    I  16 

SOME  FACTORS  VFFECTING  THE  KEEPING  QUAL- 
ITIES OF  AMERICAN  LEMONS.0 


SCOPE   OF   THE    INVESTIGATION   OF   THE   KEEPING   QUALITIES   OF 

LEMONS. 

There  is  ;i  prevailing  impression  among  fruit  handlers  that  Ameri- 
can-grown lemons  while  possessing  many  points  of  superior  attract- 
iveness arc  open  to  the  objection  that  they  arc  not  long  keepers. 
Assuming  the  correctness  of  this  report,  the  source  of  this  weakness 
demands  a  careful  study  of  the  whole  lemon  situation.  The  object 
of  this  investigation  has  been  to  gel  a  clearer  understanding  of  the 
processes  through  which  lemons  are  put  after  picking,  with  special 
reference  to  the  bearing  of  these  processes  on  the  behavior  of  the  fruit 
in  the  packing  houses,  during  transit,  and  after  it  has  reached  the 
market.  This  broadly  outlined  study  has  for  its  practical  object  the 
determination  of  conditions  affecting  the  keeping  qualities  of  the 
fruit  after  it  has  reached  the  market.  The  hope  is  also  present  that 
through  the  results  obtained  improvements  in  some  of  the  processes 
in\ esl igated  ma\   be  suggested. 

It  has  been  made  clear  by  the  work  thus  far  accomplished  that  the 
keeping  quality  of  American  lemons  i-  influenced  by  many  factors, 
some  acting  on  the  orchard,  some  in  the  packing  house,  some  in  the 
car-  during  transit,  and  some  at  points  far  distant  from  California, 
thai  is,  in  the  market-. 

LOSSES  OF  LEMONS  FROM  PARASITIC  DISEASES. 

Important  among  the  factor-  causing  the  loss  of  lemons  arc  para- 
sitic diseases  derived  from  the  orchard.  These  operate  not  only  there 
but,  unless  infected  fruit  i-  detected  and  discarded,  also  in  the  pack- 

\  series  of  physiological  studies  has  been  made  in  the  Office  of  Drug-Plant 
investigations  by  the  writer'-  of  tliis  paper  to  determine  the  relation  between 
the  present  methods  of  bringing  lemons  into  condition  fur  the  market  and  the 
keeping  qualities  shown  by  the  fruit  after  shipment.  These  results  are  based 
on  limited  data,  are  advanced  tentatively,  and  are  subject  to  modification  should 
further  investigation  require  it.  A  strong  demand  for  a  report  upon  the  results 
ilms  far  obtained,  coupled  with  the  fact  that  they  are  likely  to  be  of  some 
Bervice,  seems  to  .justify  their  publication. — B.  T,  Galloway,  Physiologist  and 
Pathologist,  <imi  chief  of  Bureau. 

[Clr.  26]  3 


4  FACTOES  AFFECTING  THE   KEEPING  QUALITIES  OF  LEMONS. 

ing  house,  and  even  after  the  fruit  has  come  on  the  market.  The 
dreaded  brown-rot  (Pythiacystis  citrophthora  Smith)  may  -land  as  a 
type  of  destructive  parasite.  Since  these  organisms  are  usually  viru- 
lent, the  diseased  fruit-  are  in  large  part  detected  before  shipment 
and  form  a  conspicuous  cause  of  loss  in  California. 

LOSSES   OF    LEMONS   FROM    BLUE    MOLD. 

A  second  type  of  trouble  comes  from  aggressive  organisms,  such  as 
blue  mold,  which,  while  not  able  to  successfully  invade  a  sound 
lemon,  are  fatal  to  fruits  which  have  been  injured  by  careless  han- 
dling at  some  point  in  their  history,  or  which  are  physiologically 
weak.  Thus,  while  blue  mold  figures  a-  an  immediate  cause  of 
considerable  loss,  it  becomes  a  source  of  danger  chiefly  after  the 
fruit  has  been  weakened  by  previous  bad  treatment.  Mold  invasion 
being  a  secondary  phenomenon  may  appear  at  any  time  in  the  his- 
tory of  the  fruit,  but  since  the  maximum  amount  of  handling,  and 
therefore  the  greatest  danger  from  bad  treatment,  is  found  during 
the  picking  process  in  the  orchard  and  in  the  subsequent  sorting  and 
handling  in  the  packing  house,  a  large  proportion  of  the  loss  from 
mold  is  probably  also  found  in  California.  Since  shipping  condi- 
tions may  introduce  violence  and  injury,  a  certain  percentage  of 
loss  due  to  this  cause  and  to  such  injuries  and  infections  as  took 
place  during  the  last  handling  in  packing  will  be  met  in  the  market 
soon  after  the  arrival  of  the  fruit.  Thus  the  blue-mold  situation 
becomes  largely  a  question  of  proper  care  in  handling.  As  the 
losses  due  to  blue  mom  are  to  a  large  degree  dependent  on  the  per- 
centage of  lemons  having  a  punctured  or  otherwise  ruptured  epi- 
dermis, the  toughness  of  the  outside  cuticle  become-  an  important 
factor  in  fruit  preservation.  The  results  of  mechanical  tests  of  the 
ease  of  puncture  as  affected  by  the  packing-house  processes  arc  sum- 
marized later  in  this  circular.  Since  injury  in  the  handling  and 
shipment  of  lemons  is  a  matter  of  study  in  the  Office  of  Field  Investi- 
gations in  Pomology  of  this  Bureau,  this  general  subject  is  not 
considered  here. 

PHYSIOLOGICAL  WEAKNESS   OF  LEMONS. 

Another  possible  seat  of  trouble  may  lie  in  weakness  caused  by  the 
processes  through  which  the  green  fruit  is  put  in  order  to  color  it  for 
the  market,  or  in  the  conditions  under  which  it  is  -lured,  either  at  the 
place  of  production  or  at  the  point  of  consumption.  This  line  of  in- 
vestigation calls  for  a  study  of  lemon  houses  and  their  operations, 
with  special  reference  to  such  processes  as  seem  likely  to  weaken  the 
fruit. 

[Cir.  26] 


FACTORS  AFFECTING  THE    KEEPING  QUALITIES  OF   LEMONS.  D 

METHODS    OF    PREPARING    LEMONS    FOR   MARKET. 

A  preliminary  study  of  the  situation  !  eloped  the  fact  that 

lemons  come  on  the  market  with  widely  differing  histories. 

Some  are  sufficiently  colored  when  they  arc  picked  from  the 
tree  and  arc  -hipped  to  the  market  as  quickly  a-  possible.  The  so- 
called  "  tree-ripe  "  lemons  are  usually  segregated  and  go  on  the  market 
a-  inferior  fruit,  it  being  generally  agreed  that  tree-ripe  lemons  do 
not  have  a-  good  keeping  qualities  as  the  fruit  which  i<  picked  green 
and  colored  artificially. 

i  •_'  >  "Sweated  fruit'1  is  picked  green  when  the  proper  diameter 
i-  reached,  and  colored  rapidly  by  storage  in  moist,  tight,  sweat 
or  sweating  ten!-  in  which  a  high  temperature  i-  maintained, 
usually  l>v  mean-  of  oil  toves  burning  in  (lie  room  with  the  lemons 
or  in  a  celler  like  room  below  the  fruit  and  separated  from  the 
storage  room  by  slatted  floors.  The  humidity  and  heat,  and  perhaps 
carbon  dioxid  and  other  gaseous  product-  of  combustion,  acting  to- 
gether bring  about  a  rapid  coloration  of  the  fruit.  Sweating  is  u-u- 
allv  resorted  to  only  when  the  price  of  lemon-  is  high  and  a  rapid 
marketing  of  the  crop  is  desired.  It  is  generally  agreed  among  lemon 
growers  that  sweated  lemon-  are  less  likely  to  keep  than  those  colored 
gradually  at  lower  temperatures.  Since  the  condition-  main- 
tained in  -weal  room-  are  highly  unnatural  and  the  result  i-  obtained 
in  a  most  unnatural  way.  some  attention  has  been  given  to  the  physio- 
logical factors  involved  in  sweating. 

By  far  the  larger  part  of  the  lemon  crop  is  picked  when  the 
desired  diameter  of  the  fruit  is  reached,  and  this  is  colored  up  by 
"curing"  at  low  temperatures  in  the  packing  houses.  In  some  place- 
where  the  water  loss  from  the  fruit  is  likely  to  he  relatively  easy  to 
control,  an  open  floor  covered  by  a  roof  i-  sufficienl  for  a  permanent 
storage  structure.  In  order  to  enable  the  manager  to  modify  condi- 
tion to  suit  the  needs  of  the  individual  lot-,  the  lemon-,  in  boxes  or 
trays,  arc  piled  up  in  carload  lot-,  and  each  pile  is  covered  by  a  heavy 
Canvas  tent,  id'  which  the  sides  and  end-  may  he  raised  or  lowered  at" 
will.  In  those  regions  where  water  loss  is  less  readily  controlled,  the 
storing  house  i-  hoarded  up  with  the  usual  wall-  and  end-.  To  secure 
uniformity  of  condition-  with  even  greater  ease,  some  growers 
have  made  use  of  cellar-  under  the  houses.  Lemons  colored  by  this 
-low  "curing"  process  may  remain  in  the  tent-  or  cellar  a-  long  as 
six  month-  or  more  if  market  condition-  require  it.  hut  usually  fruit 
i-  marketed  much  sooner. 

In  grading  and  packing  the  fruit    for  market  some  lemon  houses 
handle  the  -wealed   and   tent-cured   -oil-  separately,  hut   this  i-  not 
the  invariable  rule. 
I  i-ir.  _>;] 


6  FACTORS  AFFECTING  THE  KEEPING  i.U'ALITIES  OF  LEMONS. 

PHYSICAL  CHARACTERISTICS  OF  THE  DIFFERENT  TYPES  OF 

LEMONS. 

Lemons  are  known  to  be  a  most  variable  fruit  in  their  physical 
characteristics.  Not  only  is  this  true  of  trees  of  any  given  variety, 
but  in  some  cases  it  is  also  true  of  the  different  fruits  taken  from  the 
individual  tree.  The  manner  of  handling  water  and  fertilizers  is 
commonly  believed  to  be  of  great  importance  in  getting  smooth,  well- 
shaped  lemons.  The  lemon  varies  in  general  from  a  barrel  shape  to 
an  almost  spherical  form  marked  by  more  or  less  pronounced  pro- 
tuberant end-.  Thick  and  conspicuous  ends  detract  from  the  value 
of  the  fruit.  The  best  size  of  lemon  weighs  on  the  average  120  to 
135  grains.  Of  course  size  is  not  the  only  factor  which  determines 
the  weight,  much  depending  on  the  rind,  quantity  of  juice,  and  gen- 
eral solidity  of  the  fruit.  The  most  desirable  sizes  of  lemons  average 
300  and  360  to  the  box. 

There  are  usually  three  grades  of  lemon-,  known  as  "  fancy," 
"  choice."  and  "  standard."  The  grades  depend  on  the  general  texture 
of  the  fruit,  the  form,  and  the  color.  The  sizes  vary  from  180  to  540 
to  the  box.  but  few  lemons  are  packed  larger  than  the  240  or  smaller 
than  the  490  per  box  size.  The  better  grades  are  mostly  made  up  of 
the  fruit  of  fine  texture  and  of  good  form  picked  when  green  and 
colored  either  by  slow  curing  in  tents  or  by  sweating.  The  tree-ripe 
fruit  is  less  commonly  used  for  the  finer  select  grades,  since  many 
question  its  keeping  quality.  In  some  packing  houses  it  goes  largely 
into  an  inferior  grade,  and  at  some  seasons  of  the  year  when  the 
fruit  is  quite  small  from  400  to  500  are  packed  in  a  box.  A  very 
small  percentage  of  fruit  constitutes  the  grade  known  as  "sinkers," 
or  ''heavy  lemons."  This  type  derives  its  name  from  the  fact  that 
the  fruits  sink  in  water  when  being  washed.  They  are  usually 
spherical  in  shape  and  quite  small,  with  extremely  thin  rinds  and  a 
relatively  large  amount  of  juice. 

The  green  fruit  after  it  is  properly  cured,  either  by  sweating  or  by 
the  slower  tent  process,  possesses  a  rich  lemon-yellow  color  which  is 
seldom  found  in  the  tree-ripe  fruit. 

There  is  a  wide  variation  in  the  texture  of  lemons,  which  is  cur- 
rently believed  to  be  influenced  by  orchard  conditions  and  the  season 
of  the  year.  As  a  rule,  large,  overgrown  fruit  has  a  rougher  texture 
than  smaller  fruit.  During  the  curing  process  the  rind  is  smoothed 
down  considerably  and  the  texture  is  improved.  Tree-ripe  lemons 
usually  have  a  smoother  texture  than  the  green  fruit. 

The  rind  consists  of  the  external  epidermis  and  a  well-developed 
underlying  layer  of  soft,  spongy,  white  tissue.  This  layer  of  tissue 
contains  a  considerable  quantity  of  water,  much  of  which  evaporates 
during  the  curing  of  the  fruit,  causing  a  considerable  shrinkage  in 
the  thickness  of  the  rind.  It  is  for  this  reason  that  the  spongy  layer 
[Cir.  26] 


I "\(    rOHS    EFFECTING  THE    KEEPING  QUALITIES  OF  LEMONS.  t 

of  the  green,  freshly  picked  fruit  is,  as  a  rule,  thicker  than  thai  of 
the  tent  cured  lemon-.  Individual  lemons  display  great  variations 
in  the  thickness  of  their  rind,  a  condition  which  it  is  difficult  to 
recognize  from  the  general  external  appearance  of  the  fruit.  It 
appears  that  good,  sound,  normal-sized  fruit,  with  smooth  or  medium 
texture,  as  a  rule,  has  a  thinner  rind  than  the  rough  and  oversized 
sort-.  The  rind  of  green  fruit  varies  from  one-eighth  to  five  ix 
teenths  of  an  inch  in  thickness  and  averages  about  one-fourth  of  an 
inch.  As  stated  previously,  the  tent-cured  and  sweated  fruit  aver- 
ages somewhat  less,  while  the  "  tree-ripes "  usually  run  from  one- 
eighth  to  three-sixteenths,  and  "sinkers"  vary  from  about  one 
sixteenth  to  one-eighth  of  an  inch,  <]".<■  to  the  extreme  reduction  of 
the  spongy  la 

The  seed  content  of  the  California  lemons  is  very  small,  indeed.  A 
large  majority  of  the  fruit  is  entirely  free  from  seeds.  Now  and  then 
one  finds  a  lemon  that  contains  as  many  as  a  do/en  seeds,  sometimes 
all  developed,  but  more  often  only  partially  so.  They  occur  in  all 
grades  and  varieties  of  fruit,  but  it  appears  that  they  arc  found  more 
frequently  in  lemons  of  low  grade.  It  is  said  by  some  growers  that 
orchard  conditions  as  regards  the  soil  and  method  of  cultivation,  as 
well  as  the  general  condition  of  the  tree-,  have  an  important  bearing 
on  the  presence  of  seeds.  It  has  been  noticed  that  the  fruit  from  some 
localities  displays  a  greater  tendency  toward  seed  production  than 
that    from  others. 

The  juice  constitutes  from  30  to  :.:.  per  cent  of  the  total  weight  of 
the  lemon,  varying  to  a  considerable  extent  with  the  thickness  of  the 
rind  and  the  general  solidity  of  the  fruit.  In  the  "tree-ripes," 
"  sinker-."  and  cured  fruit  the  percentage  is  higher  than  in  the  green, 
newly  picked  lemon-,  for  the  reason  that  the  latter  have  more  water 
in  their  rind-.  The  juice  obtained  by  expression  contain-  a  consider- 
able quantity  of  mucilaginous  material,  which  gives  it  a  cloudy 
appearance.  Great  difficulty  i-  found  in  removing  this  material;  in 
fact,  all  methods  of  clarifying  tested  fail  to  make  the  juice  perfectly 
ir. 

Besides  the  citric  acid,  to  which  the  sourness  is  chiefly  due.  tar- 
taric and  malic  acid-  are  present,  lint  in  such  -mall  quantities  that 
they  are  probably  negligible  a-  to  their  effect  both  on  the  behavior  of 
the  fruit  it-elf  and  on  the  acid  determinations.  The  specific  gravity 
'Hon  juice  -how-  a  narrow  range  of  variation.  By  far  the  ma- 
jority of  determinations  give  results  approximating  L.035.  Numer 
ou-  samples  have  given  result-  a-  low  as  1.026  and  still  more  as  high 
as  I.ol.  It  was  expected  that  the  specific  gravity  of  the  juice  would 
he  governed  by  the  acidity.  Inn  this  was  borne  out  only  in  a  partial 
way.  Ii  was  found  that  either  a  decidedh  high  or  a  decidedly  low 
percentage  of  acid   i-  indicated  by  a  correspondingly  high  or  low 

[Clr.2C] 


8  FACTORS  AFFECTING  THE  KEEPING  QUALITIES  OF   LEMONS. 

specific  gravity.  This  was  especially  true  when  the  arid  content  was 
higher  than  usual.  Small  differences  in  acidity  are  not  indicated  by 
the  specific  gravity  with  any  degree  of  certainty,  the  variations  in 
the  quantity  of  mucilaginous  material  perhaps  hiding  any  change 
which  might  otherwise  be  indicated.  Experience  has  shown  that  a 
difference  of  less  than  1  per  cent  of  acid  can  not  he  foretold  by  a 
specific  gravity  determination  of  the  juice. 

CHEMICAL   CHARACTERISTICS   OF   LEMONS. 

The  chemical  study  of  lemons  as  regards  acid,  sugar,  and  water 
content  has  been  undertaken  in  the  hope  that  it  would  lead  to  in- 
formation which  would  offer  >ome  suggestions  for  improving  the 
handling  and  curing  of  the  fruit. 

ACIDS. 

The  acidity  of  the  lemon  is  considered  by  some  to  be  an  important 

factor   in   determining   its   keeping  quality,   it    being   asserted    that 

lemons  containing  a  high  percentage  of  citric  acid  resist  decay  for  a 

longer  period  than  lemons  of  a  lower  acid  content.     The  results  thus 

far  obtained  show  the  average  acid  content  of  the  different  sorts  of 

fruit  calculated  as  citric  acid  to  be  as  follows: 

Percentage  of 
acid  in  juice. 

Dark  green  fruit   (picking  stage) G.  OS 

Light  green  fruit    (picking  stage) (i.  1  i 

Tent-cured  fruit  (marketable  stage) G.  80 

Sweated  fruit    (marketable  stage) 6.  !•". 

Tree-ripe    fruit 5.  01 

-  Sinkers  " :..  68 

These  results  were  obtained  from  a  large  number  of  lemons  taken 
from  ATarious  packing  houses  and  they  indicate  that  there  is  a  differ- 
ence of  a  trifle  less  than  1  per  cent  of  acid  between  the  best  keeping 
grade  of  fruit,  the  tent-cured,  and  the  "  tree-ripes."  which  represent 
the  poorest  grade  on  the  market.  This  deficiency  seem-  too  small  to 
account  for  the  marked  difference  in  the  keeping  quality  of  these  two 
grades  of  fruit.  Other  points  of  difference  much  more  striking 
seem  to  indicate  that  other  factors  have  a  greater  bearing  on  this 
problem  than  the  acid  content.  It  has  been  found,  furthermore,  that 
tree-ripe  lemons  showing  an  average  of  6.88  per  cent  of  acid,  which 
is  exceptionally  high,  when  stored  decay  fully  as  quickly  as  other 
fruit  of  a  lower  acidity.  Sicilian  lemons  of  a  good  grade  bought  on 
(he  open  market  showed  on  the  average  6.45  per  cent  of  acid.  This 
is  less  than  is  found  in  much  California  fruit  of  a  corresponding 
grade. 

In  order  to  determine  whether  the  curing  process  has  any  marked 
influence  on  the  acidity  of  the  lemon,  a  series  of  determinations  was 
[Cir.  'JC] 


FACTORS  AFFE<    I  I  ill     KEEPING  QUALITIES  01    LEMONS. 


9 


made  during  February  and  March,  L908,  beginning  with  the  time  of 
picking  and  repeated  at  weekly  intervals  until  the  fruit  was  ready 
for  market .  as  I'ulluw  - : 


Percental 
acid  in  juice. 

February  •"•  ,;- •"■'-' 

February  10  6.  12 

Februarj  17  6.  13 

Februarj  24  6.29 

March    J  6.07 


Percentage  of 
acid  In  juice. 

March  9  6.  16 

March  10.  6.  60 

March  23  6.70 

March  30  6.  7:: 


It  will  be  seen  that  the  percentage  of  acidity  shows  a  tendency  to 
increase,  due  chiefly,  perhaps,  to  the  water  loss  accompanying  the 
curing  process. 

-i  G  VRS. 

The  study  of  the  sugars  has  thus  far  Keen  confined  to  estimating 
tlic  quantity  of  reducing  sugars  in  the  juice  of  (he  dark  green,  light 
green,  and  tent-cured  fruit.  An  attempt  has  also  been  made  to  trace 
the  development  of  reducing  sugars  as  the  fruit  develops  in  the 
orchard.  The  tests  which  were  made  during  -even  stages  of  develop- 
ment, the  last  three  stages  representing  the  dark  green,  light  green, 
and  tree-ripe  stages,  respectively,  showed  the  following  percentages 
of  sugar  in  the  juice ; 


Percentage  of 

SUgar  in  juice. 

First   stage      1.63 

Second   stage  1.'_'7 

Third  stage  1.3S     Seventh    (tree-ripe)    stage 

Fourth  stage  .  1.  19 


Percentage  of 
sugar  in  juice 

Fifth   i  dark  green)   stage  '-'.  66 

Sixth   i  lighl  green  i   stage  2.  64 

2.68 


These  analyses  show  that  there  is  relatively  little  change  in  the 
sugar  content  during  the  early  history  of  the  fruit  and  that  the  princi- 
pal development  comes  after  the  fruit  has  almost  reached  its  full  size 
and  i-  beginning  to  ripen. 

Sugar  determinations  were  also  made  upon  fruit  undergoing  cur- 
ing in  the  curing  tents.  The  estimation  was  made  during  February 
and  March.  L908,  once  a  week  from  the  time  the  fruit  was  picked 
until  the  fruit  was  ready  to  be  marketed.  The  result-  show  a  very 
low  percentage  of  sugar  compared  with  the  fruit  above  studied,  with 
no  definite  trend  toward  either  increase  or  decrease  as  the  curing  pro- 
ceed-.    The  following  tabulation  summarizes  the  analyses: 


Percental 
sugar  in 

Februarj  ■".  1.18 

February  m  1.36 

Februarj  17  1. 17 

February  i'i  1.38 

March  •_'                                  L 02 


Percentage  of 
sugar  in  juice. 

March  :>  |.  m 

March    If.  1.  19 

March  23 1.09 

March  30 i.U 


- 


10  FACTORS  AFFECTING  THE   KEEPING  QUALITIES   OF   LEMONS. 

WATER    ((INTENT. 

Some  investigations  were  begun  relative  to  the  loss  of  water  from 
lemons  while  undergoing  curing  both  by  the  tent-curing  method  and 
by  sweating.  The  green  fruit  as  it  comes  from  the  orchard  has  a 
rather  thick  rind  with  considerable  spongy  tissue.  During  the  cur- 
ing this  tissue  shrinks  to  a  considerable  extent  and  the  rind  becomes 
somewhat  thinned  and  toughened.  This  change  is  believed  to  be  due 
chiefly  to  the  evaporation  of  water  from  the  rind.  In  order  to  deter- 
mine the  extent  of  this  evaporation,  both  as  to  the  total  amount 
evaporated  and  the  stages  of  the  curing  process  during  which  most 
of  it  occurs,  a  convenient  quantity  of  lemons  was  placed  in  a  separate 
box  and  kept  in  a  tent  with  about  a  carload  of  other  fruit  and  weighed 
once  a  week.  The  lemons  were  divided  into  two  lots  by  a  partition 
through  the  box.  the  bottom  of  one-half  being  lined  with  paper. 
This  was  done  with  the  object  of  determining  the  extent  to  which 
evaporation  is  retarded  by  lining  the  boxes  with  paper,  a  practice 
which  is  sometimes  resorted  to  during  extremely  dry  weather.  The 
results  obtained  during  December,  1907,  and  January,  February,  and 
March,  1908,  are  shown  below: 

Table  I. — Loss  of  water  in  lemons  while  curing  in  tent  31. 


December  16 . 
December  23 . 
December  30 . 
January  6 

January  13  ... 
January  20... 


Date. 


Bi  ixes  lined  with 
paper. 


b"\e~  without  paper 
lining. 


Weekly 

llivs. 


I'i  r  CI  at- 


l.-ll 

1.07 

.97 

1.17 

1.45 


Total  loss. 


Weekly 

loss. 


Percent.        I  < 


1.41 
2.47 
3.42 
4.45 
5.97 


I    II 

l   I  ; 


1.20 
1.64 


Total  loss. 


Pel    ,  ,   n! 


1.46 
2.55 

3.50 
4.68 
6.23 


Table  II. — Loss  of  water  in  lemons  while  curing  in  tent  59. 


January  27  .. 
February  3.. 
February  10 
February  17. 
February  24 . 

March  2 

March  9 

March  16.... 

March  23 

March  30.... 
April  6 


llalc. 


Boxes  lined  with 
paper. 


Boxes  without  paper 
lining. 


Weekly 

lovS. 


P<  r  cent 


1.09 

.  92 

1.10 

.87 

.'.HI 

1.49 
1.27 
1.50 
2.95 
2. 30 


Total  loss. 


Per  ••'  nt. 


1.09 
2.00 
3.117 
3. M| 
4.77 
6.2] 
7.40 
8.  75 
11.50 
13.59 


Weeklj 
loss. 


Total  loss. 


1.04 
.97 
.98 

.99 

.97 

59 

1.30 

,ii 

2.77 

2.  22 


I;  r  ct  nt.         1''  r  a  a!. 


1.04 
2.06 
8.  23 
3. 97 

4.94 

6.  11 

7.  67 
9.00 

11.57 
13.54 


[Cir.  2C] 


FA<    rORS   \l  !  E(    I  INC  THE    KEEPING  QUALITIES  OF   LEMONS.         11 


The  following  tabulation  shows  the  percentage  of  total  water  loss 
during  twenty-two  days  from  three  sorts  of  fruit: 

Tabu    III.     Loss  of  water  in  lemons  while  curing  for  twenty-two  dnj/s. 


sort  ol  fruit. 


Boxes  lined  B^l1'1'- 


Per  cent.        Per  cent. 

Dark  green  

Uxlit  grreen 2.86 

•■  Tree-ripe  " 2. 73  ;s.  1 1 


These  experiments  shew  thai  the  loss  « •>  i"  water  from  the  fruit  does 
not  increase  or  decrease  week  by  week  with  any  regularity.  Some 
weeks  show  a  decided  increase  and  arc  immediately  followed  by  a 
corresponding  decrease.  The  explanation  for  these  irregularities  can 
probably  be  found  in  existing  weather  conditions,  especially  as  regards 
humidity  and  wind.  A  wry  humid  day  would  cause  a  decrease  in  the 
evaporation  from  the  fruit,  whereas  a  high  wind,  even  though  not 
exceptionally  <hy.  would  penetrate  the  usual  form-of  packing  house 
and  convey  the  moisture  away  through  various  doors,  cracks,  and 
other  openings  to  such  an  extent  as  to  increase  the  water  loss  from 
the  fruit.  Careful  manipulation  of  the  tent  and  good  judgment  as 
to  when  and  how  much  to  ventilate  the  fruit  would  doubtless  do  much 
to  minimize  these  fluctuations. 

In  comparing  the  results  shown  in  different  tents  it  must  be  borne 
in  mind  that  the  respective  location  of  the  tents  has  a  very  material 
effeel  on  evaporation.  A  tent  which  i>  in  close  proximity  to  the  open 
side  of  the  house  or  to  door-  and  corridors  where  currents  of  air  can 
circulate  around  it  would  necessarily  show  wider  fluctuations  in  its 
evaporation  than  a  tent  located  in  the  center  of  the  house  and  well 
protected  from  external  atmospheric  changes. 

In  sweat  rooms,  where  the  fruit  is  kepi  at  a  much  higher  tem- 
perature, very  differenl  conditions  are  met  with.  Owing  to  the  high 
heat  with  lower  relative  humidity  the  evaporation  take-  place  much 
mole  rapidly.  The  total  percentage  of  water  evaporated  at  different 
intervals  from  the  fruit  in  such  a  -went  room,  the  fruit  being  sweated 
twenty  days,  a  period  considerably  longer  than  is  usually  required, 
is  shown   lielow  : 


Percentage  of 
water  evaporated 

February  •_':: 

February   25    0.85 

Februan    26    i'.  10 

Februarj    ^7      •_'.  Tc 

Februarj    28 3.40 


Percentage  of 
water  evaporated. 

March  1 ::.m 

March  .".    i  60 

March  'a    6.  in 

March   13 8.05 

March  Hi 9.25 


t l'lr.  26] 


12         FACTORS  AFFECTING  THE  KEEPING  QUALITIES  OF  LEMONS. 
KEEPING  QUALITIES  OF  LEMONS. 

To  anyone  who  has  carefully  examined  lemons  as  they  come  freshly 
cut  from  the  orchard  or  as  they  hang  on  the  tree  it  is  clear  that  the 
fruit  is  oftentimes  extremely  variable  in  size,  shape,  and  texture.  It 
is  quite  generally  held  that  lemons  of  a  certain  form  are  likely  to 
prove  good  keepers,  while  those  having  other  forms  are  liable  to 
decay  early.  The  unsymmetrical,  usually  undersized  lemons  grown 
in  the  bright  sun  are  thought  to  be  poor  keepers,  while  those  from 
the  portions  of  the  tree  where  the  fruits  are  well  enveloped  by  leaves 
and  have  a  good  size  and  symmetrical  form  are  believed  to  have  good 
"life."  It  has  not  been  practicable  thus  far  to  experimentally  test 
these  suppositions,  but  it  seems  from  what  has  been  done  that  there 
is  a  considerable  degree  of  variability  in  the  keeping  qualities  of 
lemons  from  the  same  orchard  and  probably  from  different  parts  of 
the  same  tree. 

RELATION    TO   STRUCTURE. 

Certain  structural  features,  viz.  those  belonging  to  the  rind,  seem 
to  be  especially  important  in  this  connection.  The  rind,  which  con- 
sists of  a  layer  of  white,  spongy  packing  tissue  having  a  very  variable 
thickness,  is  covered  on  the  surface  by  the  epidermis.  This  covering 
consists  of  a  layer  of  cells  so  modified  chemically  as  to  be  almost  im- 
pervious to  water.  The  degree  of  imperviousness  is  greatly  increased 
by  a  dense  outer  cuticle  of  a  very  resistant  material  which  is  prac- 
tically waterproof.  There  are  a  vast  number  of  small  pores  (sto- 
mata)  in  the  epidermis,  through  which  gases  enter  and  water,  as 
vapor,  escapes.  These  stomata  open  into  small  chambers  in  the  outer 
part  of  the  rind. 

Additional  characteristic  structures,  known  as  oil  glands  from  the 
substance  which  is  formed  in  them  and  which  they  retain  until  the 
skin  dries  up,  are  found  embedded  in  the  outer  part  of  the  rind  at 
different  distances  from  the  epidermis.  The  oil  in  these  glands  is  a 
volatile  product,  giving  the  characteristic  lemon  odor  to  the  fruit. 

As  has  been  already  indicated,  the  losses  assigned  to  blue  mold  are 
in  a  very  large  measure  due  to  the  development  of  the  fungus  fol- 
lowing injuries.  It  is  probable  that  the  true  blue  mold  can  not  pene 
trate  the  uninjured  epidermis  of  a  healthy  lemon,  but  when  a  break 
occurs  it  is  able  to  enter  and  bring  about  the  characteristic  rot.  The 
development  of  the  defensive  outer  layers  of  the  rind  is  a  matter  of 
great  importance  in  view  of  the  ease  of  producing  slight,  but  fatal, 
injuries  to  the  fruit. 

To  test  the  strength  of  this  defense,  a  simple  puncture  experiment 
was  devised.  It  consisted  essentially  of  an  apparatus  so  constructed 
as  to  enable  one  to  apply  known  and  regulated  pressure  to  a  blunt 
point  in  such  a  way  as  to  get  the  amount  of  pressure  needed  to  force 
the  point  through  the  epidermis.  The  needle  tip  was  found  to 
[Cir.  26] 


FACTORS    '  I  I  I  (    II  N<:    III  i:    KEEPING  QUALITIES  OF   LEMONS.         13 

puncture  the  epidermis  and  bring  oil  to  the  surface  with  more  readi- 
ness when  it  was  applied  directly  over  an  oil  gland  —that  is,  on  the 
surface  of  one  of  the  projecting  papilla'  than  when  applied  in  the 
sunken  place  between  these.  It  appears  that  the  nearer  the  oil  glands 
are  to  the  surface  the  greater  the  ease  of  rupture.  In  tree-ripe 
lemons  it  seems  from  the  evidence  thus  far  gathered  that  the  outer- 
most glands  are  likely  to  be  less  protected  than  in  the  fruit  which  is 
picked  green.  This  would  seem  to  indicate  that  tree-ripe  fruit 
might  -how  a  greater  loss  from  mold  due  to  injury  than  fruit  picked 
\\  hile  green. 

In  a  similar  study  of  tent  cured  fruit,  a  resistance  markedly  greater 
than  in  tree-ripe  lemon-  was  shown,  indeed,  the  resistance  to  punc- 
ture in  tent-cured  fruit  seems  to  be  double  that  of  tree-ripe  lemon-. 
This  difference  is  probably  (\\io  in  part  to  other  factors  than  the 
absolute  strength  of  the  wall-  of  the  epidermis,  hut  the  result  rep 
resents  practically  the  relative  liability  to  damage  dependent  on 
the  structure  of  the  outer  tissues  of  the  lemon.  It  was  found  that 
lie'  tissue  beneath  the  tough  outer  epidermis  was  able  to  offer  very 
little  resistance  when  the  point  of  a  needle  hail  passed  through  the 
epidermis. 

Lemons  are  frequently  subjected  to  steady  pressure  of  various 
degrees  of  intensity,  and  are  preserved  from  injury  by  the  general 
strength  of  their  tissues  throughout.  Under  these  circumstances,  the 
white,  pulpy  packing  tissue  between  the  epidermis  and  the  segments 
play-  an  important  part.  The  thickness  of  this  tissue  varies  very 
widely.  In  the  so-called  "•-inker-."  which  form  a  case  of  an  extreme 
reduction,  this  tissue  forms  a  very  inefficient  protection  against  in- 
jury.    Hence,  ''sinkers  "  might  !"■  expected  to  he  poor  shippers. 

ii  \  1 1  1 1 1  . 
The  relation  of  coarseness  of  texture  to  losses  is  not  very  clearly 
marked.  In  general,  coarse  lemons  have  a  strong  development  of 
rind  tissue.  But  many  smooth  lemon-  are  equally  well  protected. 
The  thickness  of  the  epidermis  and  the  consequent  ability  of  the 
lemon  to  withstand  wear  i-  well  tested  in  the  box  during  shipment, 
w  hen.  as  frequently  happens,  the  jar  of  the  car  in  stopping  and  start 
ing  is  transmitted  to  the  fruit  in  the  box.  The  resull  follow-  that  the 
fruit  i-  ••  rasped  "  on  rough  surfaces  of  the  shook,  particularly  of  the 
end-  and  middle  crosspieces  when  they  are  not   planed. 

Ml    I  IK  'li    ol     (1    in  M.. 

Tin'  keeping  qualities  of  different  types  of  lemon-  also  depend 
largely  on  the  method  of  treatment  to  which  they  are  subjected  to 
bring  them  into  marketable  condition.     Although  the  inh<  on- 

dition  of  the   fruit,  ^\\\r  partly  to  its  early  history,  will  determine 

rcir.  20] 


14         FACTORS  AFFECTING  THE  KEEPING   QUALITIES   OF  LEMONS. 


its  ability  to  resist  decay  to  some  extent,  there  is  reason  to  believe 
that  the  method  of  curing  is  an  important  factor  in  determining  the 
life  of  the  lemon  on  the  market.  The  lemon  growers  as  a  rule  agree 
that  the  so-called  sweating  process  of  curing  fruit  has  a  deteriorating 
effect,  although  no  definite  test<  have  been  made  which  would  fully 
substantiate  this  belief.  The  sweating  process  is  resorted  to  only 
when  the  briskness  of  the  market  necessitates  a  rapid  coloring  of  the 
fruit.  The  grower,  although  he  realizes  the  possibility  of  endan- 
gering the  quality  of  his  fruit,  has  at  present  no  other  method  of 
curing  lemons  rapidly,  and  is  therefore  compelled  to  make  the  most 
of  the  process. 

The  tree-ripe  fruit,  as  has  been  stated  elsewhere,  is  thought  to  be 
inferior  to  the  tent-cured  sort,  and  is  kept  in  the  packing  house  as 
short  a  time  as  possible.  After  being  washed  and  graded,  it  is 
immediately  put  upon  the  market,  as  a  rule,  for  unnecessary  delay  in 
the  packing  house  will  only  shorten  its  life  on  the  market. 

The  point  to  be  investigated,  therefore,  is  the  relative  keeping 
qualities  of  these  three  sorts  of  fruit.  With  this  object  in  view,  a 
limited  series  of  storage  tests  was  made  in  the  spring  of  1908. 

All  the  fruit  was  shipped  to  Washington,  D.  C..  and  stored.  The 
entire  lot  was  carefully  examined  once  a  week  for  three  or  four  weeks, 
and  then  every  two  weeks  during  the  remainder  of  the  test.  Careful 
note  was  made  of  the  form  of  decay  which  was  met  with,  in  order  to 
get  more  information  as  to  what  varieties  of  decay  are  most  destruc- 
tive after  the  fruit  arrives  on  the  market.  The  following  are  the 
summarized   results: 

Table  IV.  —  Loss  nt  lemons  from  all  forms  of  decay  during  sijctei  n  Wi  <  ks  in  storage. 


No.  of    Int. 

Tent-cured 
fruit. 

ripe 

fruit. 

Sw  eared 
fruit. 

1                                                                                                              

I'l  r  C<  :;! 

11.5 

19  0 

■A  0 

A;'  <■/  lit. 
I,.-.  (1 
49.  7 
54.0 
9    i 
j$9  ii 

I'<  r  a  i'l 

72.0 

23.1 

5                                                                           

"  Two  weeks  lessi 
Table  V. — Percen  ag(  -<    otal  loss  of  lemons  due  apparently  to  blue  mo 


No.  of  lot. 


Tent-cured 

Tree-ripe 

fruit. 

fruit. 

i'i  !•     i 

Per  • 

n 

18.5 

17.6 

52 

.1 

i.;  8 

76.0 

46.3 



Sw  eated 
fruit. 


72.0 

62.  - 


o In  these  fig  Hrst  two  weeks  in    torage  are  not  included,  tor  l  lie  different  forms  oi  di  i 

were  not  registered  separately.     During  the  early  weeks  the  blue  mold  predominati  d  ow  ing  perhaps 
to  the  mechanical  injury  received  in  the  packing  house  and  in  transit. 

[Cir  26] 


I   it    CORS    EFFECTING  THE   KEEPING  QUALITIES  OF   LEMONS.         L5 

A  careful  study  of  Table  1  \'  will  indicate  clearly  the  superiority  of 
the  tent-cured  over  the  tree-ripe  fruit.  In  each  of  the  five  lots  this 
point  is  well  brought  out.  It  will  be  further  noticed  that  the  amount 
of  rot  in  the  tent-cured  fruit  is  very  nearly  the  same  in  all  five  lot> 
(if  lot  5  had  been  kept  two  weeks  longer  it  would  probably  have 
-how  ii  nearly  30  |>er  cent  of  deca\  ),  thus  showing  that  there  is  no 
material  difference  in  the  fruit  which  had  been  obtained  from  the 
coast,  the  foothills,  and  the  inland  districts. 

I  he  results  obtained  from  sweated  fruit  indicate  a  rather  peculiar 
condition,  which  it  is  impossible  to  explain  at  present.  Neither  lot 
weated  as  thoroughly  as  is  the  custom,  nor  were  both  lots  sweated 
exactly  alike,  which  facts  may  account  to  some  extent  for  the  great 
difference  in  the  result-.  The  variation  in  decay  is  not  the  only 
point,  however,  in  which  these  two  lot-  of  fruit  differed.  Lot  3  was 
excellent  fruit,  with  a  soundness,  texture,  and  color  well  worthy  id' 
the  best  fancy  grade,  while  lot  •_'  was.  almost  from  the  beginning  of 
the  tests,  of  such  unpresentable  appearance  as  to  make  it  practically 
unmarketable.  The  causes  underlying  these  great  differences  are  not 
understood  at  present,  hut  the  results  "unite  a  more  extended  study 

of  the   matter. 

THE  MOST  SERIOUS  CAUSES  OF  DECAY  OE  LEMONS. 

An    important    phase  of  the   whole  situation   as   regards  keeping 

qualities  is  the  matter  of  the  different  forms  of  decay  met  with  in 
these  tests.  In  the  first  few  examination-  no  definite  record  was  kept 
of  each  form,  hut  the  blue  mold  predominated,  a  condition  which 
lie.  nine-  prevalent  after  much  handling  of  the  fruit,  a-  i-  the  case  in 
sorting,  packing,  and  shipping.  After  a  few  week-  it  became  appar- 
ent, however,  that  a  different  form  of  decay  was  beginning  to  appear, 
which  suggested  the  necessity  of  keeping  a  close  watch  on  the  relative 
growth  of  each  form.  Table  V  -how-  the  percentage  of  the  total  rot 
which  was  apparently  due  to  blue  mold  when  -i'rw.  Considerable 
difference  is  found  among  (he  various  lots.  The  amount  of  care  exer- 
cised in  handling  the  fruit  at  tin'  different  place-  where  it  was  obtained 
and  the  fact  that  it  was  not  all  shipped  over  the  same  route  might  go 
far  in  explaining  the  di fference. 

A-  many  a-  five  apparently  distinct  types  of  slow  disease  id'  the 
rind  were  -ecu.  oftentimes  having  very  striking  form  and  color  char- 
acteristics. These  were  not  studied,  since,  apart  from  injured 
appearance,  the  loss  due  to  them  directly  appeared  to  he  hut  -mall. 
They  may.  however,  posses  greater  significance  by  opening  the  way 
for  the  more  actively  destructive  power-  of  the  mold. 

Finally,  there  is  a  \er\  prevalent  form  of  decay  resembling  in 
appearance  and  in  odor  the  virulent   brown-rot  of  the  citrus  region. 

[Cir.  26] 


16         FACTORS  AFFECTING  THE  KEEPING  QUALITIES  OF  LEMONS. 


The  conspicuous  symptom  is  a  brownish  discoloration,  which  may 
appear  anywhere  on  the  lemon,  followed  by  softening,  discoloration, 
and  a  spreading  of  the  affected  area,  which  in  time  involves  the  entire 
lemon.  The  progress  of  the  decay  can  be  noted  by  the  brown  color 
and  disintegration  of  the  tissue-. 

The  following  table  shows  an  interesting  condition  a<  to  the  periods 
when  the  greatest  and  smallest  amount  of  decay  takes  place : 

Table  VI. — Decay  in  lemons  in  storage  for  different  periods. 


in  storage. 

Lot  1. 

Lot  2. 

Time 

Tent-cured 
fruit. 

Tree-ripe 
fruit. 

Tent-eured 
fruit. 

Tree-ripe 

fruit. 

Sweated 
fruit. 

Per  a  nt. 
1.6 

2.9 
2.2 
1.8 
3.1 
::.  2 
5.0 
7  2 
8.  l 
14.0 
13.4 

!'•  i  cent. 

10.0 

17.4 

5.5 

1.0 

I  E 

12.6 

14.9 
16.5 

15. 3 

Per  n  ill. 
0.0 
.5 
1.9 

.0 

.4 

.0 
1.5 
2.7 
2.0 
5.4 
(i.l 

/••  r  cent. 

5.  1 

6 

3.5 

2.  0 

2.2 

1.4 

6.8 

6.8 

12. 2 

11.0 

/■<  r  cent. 
3.1 

1                 

1  ,.7 

2                   

13.2 

;i                           

3.4 

4                

3.6 

6                    

3.7 

8        

2.2 

10                            

16.3 

12                             

21    8 

14                               

19.6 

16                               

27.7 

Lot  3. 

Lot  4. 

Lot  5. 

Time  in  storage. 

Tent-cured 
fruit. 

Tree-ripe 
fruit. 

Sweated 
fruit. 

Tent-eured 
fruit. 

Tree-ripe 

fruit. 

Tent-cured 
fruit. 

Tree-ripe 
fruit. 

Weeks. 

On  arrival 

1   

Perct  n(. 
0.0 
3.3 

.0 
.6 
.8 

2.4 
3.9 
5.1 
7.:: 
8.6 
14.2 

/■-  r '■'Hi. 

O.S 

2.8 

.0 

.0 

.3 

.9 

5.8 

9.0 

7.8 

14.0 

11.2 

/'.  r  a  nt 
0.0 
2.1 
1.0 

.7 
1.1 

.0 
2.9 

1.  12 
3.4 
1.9 

2.  1 

Perct  nt. 

1.2 
1.3 
4.3 
2.2 
.5 
1    - 
2.3 
4.8 
4.5 
7.4 
9.7 

Per  a 

4.8 
1.2 

3.0 
4.  9 
4.2 
3.9 

22. 1 

17.:; 

27.  (', 

/'i  r  a  hi. 

2.8 

6.8 

1.8 

.9 

.4 

1.4 

.9 

3.  3 

3.5 

1.1 

Per  < 

4.1 
8.8 

2 

2.7 

3 

1.6 

4 

1.2 

6 

2.8 

8                

2.1 

10 

4.4 

12 

t;,  3 

n 

13.0 

16 

The  principal  tiling  to  be  observed  here  is  the  interval  of  minimum 
decay  occurring  about  three  or  four  weeks  after  the  arrival  of  the 
fruit  in  storage.  After  this  more  or  less  extended  period  the  decay 
often  increases  rapidly  from  week  to  week.  When  it  is  remembered 
that  the  decay  during  the  first  few  weeks  was  mainly  due  to  blue 
mold,  it  seems  reasonable  to  suppose  that  the  period  of  decreased 
decay  follows  after  the  majority  of  the  fruit  injured  mechanically 
during  curing  and  packing  and  while  in  transit  has  succumbed  to  the 
attack  of  the  blue-mold  fungus.  In  other  words,  it  constitutes  the 
period  of  the  greatest  freedom  from  any  form  of  decaj^.  The  fruit 
later  shows  signs  of  weakening,  however,  and  collapse,  the  symptoms 
of  which  have  already  been  discussed,  then  becomes  the  chief  source 
[Clr.  26] 


FACTORS    EFFECTING  THE    KEEPING  QUALITIES  OF   LEMONS.        17 

of  loss.     The  lemon  thu^  weakened  again  offers  an  opportunity   for 
blue-mold  attack.     It   must   be  remembered  that   these  observations 
were  made  on  tests  of  a  comparatively  small  quantity  of  fruit.     Ex 
periments  along  i h is  line  will  be  continued  on  a  larger  scale. 

CONCLUSION. 

From  the  work  thus  far  accomplished  certain  general  conclusions 
seem  to  follow,  but  in  indicating  them  it  should  be  distinctly  borne  in 
mind  that  they  are  advanced  in  a  tentative  way  and  may  be  more  or 
less  modified  as  these  investigations  progress.  It  is  probable  that  the 
keeping  quality  of  American  fruit  in  the  market  is  affected  by  the 
manner  of  handling  in  the  course  of  its  history,  especially  during  the 
later  stages  of  handling  in  California,  during  transit,  and  in  the 
whole-ale  houses.  Rough  handling  results  largely  in  cases  of  blue 
mold.  A  well-marked  physical  breakdown,  resulting  apparently 
from  brown-r  >t  infection,  seems  to  cause  most  serious  losses  after  the 
fruit  has  been  stored  for  some  week-  or  months. 

Tn  a  series  <>(  experiments  designed  to  demonstrate  the  communi- 
cability  of  this  disease  under  the  condition-  of  storage  present,  nega- 
tive results  at  first  seemed  to  point  to  a  physiological  breakdown,  but 
a  study  of  the  decaying  lemon-  by  Mr-.  Flora  W.  Patterson.  Mycolo 
gist  of  the  Bureau  of  Plant  Industry,  revealed  the  presence  in 
practically  all  cases  of  fungal  hyphse  resembling  those  of  Pythia- 
cystis,  tin'  brown-rot.  Investigations  in  the  office  of  Fruit-Disease 
[nvestigations,  under  the  direction  of  Mr.  M.  B.  Waite,  Pathologist, 
have  demonstrated  the  presence  in  much  of  the  diseased  fruit  of  the 
wither-tip  organism,  Colletotrichum.  One  or  both  of  these  organisms, 
and  perhaps  other-  also,  are  therefore  apparently  the  cause  or  causes 
of  the  brownish  rot  which  appears  in  the  lemon-  after  they  have 
been  some  week-  in  storage.  Infection  probably  takes  place  in  Cali- 
fornia and  the  disease  remains  undeveloped  until  week-  after  arrival 
in  the  eastern  market. 

Approved : 

James  Wii  son, 

Seen  tary  of  .  \.gricultiin  . 

Washington,  D.  ('..  May  J',.  1909. 

O 


'  croi  i  t    ut-    hL  UKIUA 


3  1262  08928  9499 


